In order to make liquid crystal panels lighter and thinner, technologies of integrating driving chips peripheral to panels into the panels or into flexible printed circuit boards (FPCB) have been developed. For example, these technologies include chip on glass (COG), chip on FPCB (COF), and WOA. Hence, a gate driver and a source driver in a liquid crystal display device are able to be directly integrated on a glass substrate and to directly utilize wires on the glass substrate to receive data and clock signals from a timing controller.
In terms of signal transmission, since the timing controller is disposed on a printed circuit board (PCB), signals output by the timing controller must be transmitted through the wires on the PCB to the glass substrate and then through wires on the glass substrate to the driving chip on the panel. Moreover, FIG. 1 is a schematic diagram showing signal transmission. As shown in FIG. 1, a transmission terminal 110 includes an output impedance ZO1, and the output impedance ZO1 is an equivalent impedance viewed from an output port of the transmission terminal 110. A receiving terminal 120 includes an input impedance ZI1, and the input impedance ZI1 is an equivalent impedance viewed from an input port of the receiving terminal 120. When the output impedance ZO1 and the input impedance ZI1 do not match, reflection loss occurs, thereby causing distortion in signals transmitted by the transmission terminal 110.
Therefore, for a liquid crystal display device, the timing controller is equivalent to the transmission terminal for the signals, and the driving chip is equivalent to the receiving terminal for the signals. Also, the timing controller must transmit the signals to the driving chip through two different types of wires, so that the timing controller and the driving chip often cause distortion in the signals due to impedance mismatching. At this moment, voltages output by the driving chip are not uniform, so that display quality of the liquid crystal display device is lowered.